The present invention relates to indicator devices for a motor vehicle, and more particularly to those which are of the type including a part forming a side return or wing return.
The expression xe2x80x9cside returnxe2x80x9d or xe2x80x9cwing returnxe2x80x9d designates the part of an indicator lamp which is intended to be positioned not on the front or rear face of a vehicle, but on one flank of it, in the region of the part where a wing is connected to this front or rear face.
The regulations stipulate or tolerate xe2x80x9clateral repeaterxe2x80x9d devices, which consist of indicator lamps intended to operate at the same time as a main indicator lamp emitting light forwards or rearwards of the vehicle, the lateral repeater lamp simultaneously emitting light at the side of the vehicle, to the right or to the left. Such lateral repeater lamps, conventionally provided with a light source and with a reflecting mirror mounted in a housing closed by glazing or a bezel, have a minimum specific size which can make them awkward to install on the sides of the vehicle.
Attempts have already been made to solve this problem by providing various means such that the indicator lamp emits light both in a direction substantially parallel to the axis of the vehicle and in a direction substantially perpendicular to the axis of this vehicle, while using only one single light source. For example, document U.S. Pat. No. 3,969,621 describes a lighting device including a light source at the focus of a parabolic reflector, a total-reflection optical component being arranged on the path of at least one half of the light beam, in such a way as to direct this half of the light beam laterally with respect to the vehicle, while the other half can emerge from the lighting device in the axis of the vehicle.
Document FR-A-2 378 234 describes a corner lamp for a motor vehicle including a reflector, a light source and a transparent catadioptric element placed transversely to the axis of the reflector in such a way as to intercept at least a part of the light beam reflected by the reflector, this catadioptric element featuring needles on its inner face which each exhibit, at least in the useful illumination window, at least one facet defining, with the flat outer surface of the catadioptric element, a deviating prism the inclination of which is such that the lamp emits a second illumination flux adjacent to a first flux.
There is also known, from document FR-A-2 695 362, an indicator lamp with lateral visibility, which includes a light source, means for coloring the light originating from this source, a mask including opaque areas and transparent areas distributed in such a way as to attenuate the perception of the coloring means when the lamp is unlit and observed from the outside, the lamp further comprising, in a lateral region of the mask, at least one uncolored transparent bar extending substantially parallel to the overall direction of the beam exiting the mask, the bar forming a light guide for the radiation originating from the source in its direction and possessing a free end face which is inclined so as, by total reflection, to re-emit this radiation in a general direction which is essentially transverse to the overall direction.
The indicator lamps constructed according to the teachings of these documents feature a relatively substantial size, which is dictated by the means used to deflect laterally some of the light emitted in the axis of the vehicle, and the shape of the protection glazing is itself dictated by these deflection means. Such a bulky size of the lamp, and such a shape of the glazing, may often prove to be incompatible with the requirements of the motor-vehicle manufacturers. This is because the space available for installing lighting or indicator devices is more and more restricted, both at the front and at the rear of a modern motor vehicle. Moreover, the constraints of aerodynamics and the ideas of the stylists lead to shapes which are often very different from those which result solely from technical considerations.
It results therefrom, for example, that the glazing of a lighting and/or indicator device may extend into regions where it no longer has any optical function, but solely an aesthetic role, in the concern for continuity of shapes or of lines. It is then usual to arrange, in these regions, between the protection glazing and the bodywork elements of the vehicle, a styling mask provided with an appropriate coating, or, in the absence of a mask, to shape the housing of the lighting or indicator device, which is then visible behind the protection glazing, so that it has the desired appearance.
One example of a lighting and/or indicator device including a part forming a side return in which the protection glazing has no optical function is given by document FR-B-2 732 932, which sets out to solve the problem of making the surface of the side return of the indicator device come as near as possible flush with the level of the surface of the bodywork, when this type of indicator device is mounted on the bodywork.
There is also known from document U.S. Pat. No. 4,680,680 an indicator device in which the regions of the glazing can fulfil different functions, with the aid of colored filters and of Fresnel prisms arranged at 45xc2x0.
There are also known, for example from documents EP-A-0 830 984, U.S. Pat. No. 4,929,866 or EP-A-0 908 666, indicator devices in which a plate inclined by a given angle with respect to the exit glazing possesses striations inclined at 45xc2x0 with respect to the glazing so as to reflect the light rays emitted by light-emitting diodes situated close to the edge of the glazing.
The present invention falls within this context, and its object is to provide a lighting or indicator device the size of which, in particular the thickness, is small so as to allow it to be installed easily in the spaces of a vehicle where volume is restricted and where it is nevertheless desired to make available a lighting, indicator or lateral repeater function, such a lighting or indicator device being, moreover, simple to assemble in spaces of restricted volume, reliable in its operation, the photometric performance meeting the regulations in force, and inexpensive.
Thus the object of the present invention is a lighting or indicator device for a motor vehicle, including at least one light source, a reflector and a light-diffusing plate.
According to the present invention, the reflector and the light-diffusing plate consist of smooth, continuous and substantially flat elements forming a small but non-zero angle between them and delimiting between them a substantially prismatic volume.
According to other advantageous and non-limiting characteristics of the invention:
the light source is arranged in the vicinity of the large base of the prismatic volume bounded by the reflector and the light-diffusing plate;
the extremity of the reflector and the extremity of the light-diffusing plate which are furthest from the large base of the prismatic volume are contiguous;
the extremity of the reflector and the extremity of the light-diffusing plate which are furthest from the large base of the prismatic volume are spaced by a length less than the length of the large base of the prismatic volume,
the light-diffusing plate is produced from a first transparent material possessing a first refractive index and in which are embedded inclusions made of a second transparent material possessing a second refractive index different from the first one;
the reflector is produced in the form of a transparent plate;
arrangements for deflecting the light are formed on the face of the reflector which is furthest from the light source;
that transparent plate forming the reflector is traversed by the light originating from a second light source;
the second light source interacts with a mirror so as to constitute a lamp of the vehicle;
the reflector and the light-diffusing plate are arranged in a housing, and the reflector consists of a portion of the housing;
the reflector is produced in the form of a plate made from a first transparent material possessing a first refractive index and in which inclusions are embedded made of a second transparent material possessing a second refractive index different from the first one;
one face of the plate forming the reflector, opposite to that which is turned towards the light source, is coated with a light-reflecting material;
the light source consists of a plurality of light-emitting diodes;
the light source consists of a plurality of incandescent bulbs;
the light source consists of a fluorescent tube.
Other objects, characteristics and advantages of the present invention will emerge clearly from the description which will now be given of an embodiment given in a non-limiting way by reference to the attached drawings.